Larry M. Bush, MD, FACP

In the current era of medicine, the creation of practice guidelines and the care we provide to our patients are based on a combination of data gathered from 1) well-conducted, prospective, randomized clinical trials; 2) large cohorts of retrospective observational studies; and when these are lacking, 3) reliance on our knowledge and understanding of firm, basic scientific principles, as well as our individual and collective accumulated experiences. Nevertheless, notwithstanding our best intentions to “stick to evidence-based medicine,” and irrespective of medical or surgical specialty, a significant portion of our daily clinical practices remain rooted in dogma, dictum and tradition. In other words, “that is how we always did it.” The field of infectious diseases is no exception, particularly surrounding the general overall concept of anti-infective therapies and specifically in relationship to how, when and why we prescribe antibiotics and for how long they are administered. Traditional infectious diseases practices that were once strictly adhered to — such as treating asymptomatic bacteriuria before total joint arthroplasty surgery, prolonged pre-emptive empiric administration of broad-spectrum antibiotics for type III open orthopedic fractures, and double or dual coverage for infections caused by Pseudomonas aeruginosa — have since either convincingly been disproven as being beneficial or have come under closer scrutiny and are now carried out only in certain specific circumstances.

Today we have access to a multitude of new and novel medications, biologic agents, medical devices, imaging modalities, and surgical and nonsurgical invasive procedures, which have transformed the practice of internal medicine from what was essentially a diagnostic profession to one that is now heavily focused on treatment. Although the subspecialty of ID has been treatment oriented for many years, the advent of many new and sophisticated tests means we should turn our attention to potential improper use of the clinical laboratory — a major cost center in any health care system. This brings up the less often addressed but surely relevant concept of laboratory stewardship.

Each day, blood and cerebrospinal fluid cultures are considered the most significant tests that are requested from the clinical microbiology laboratory by essentially all hospitals. Objectively speaking, the term “bacteremia” simply refers to the detection or presence of a bacterial organism in the bloodstream. No more or no less. Analogous to a chemical assay that identifies elevated potassium (hyperkalemia) or diminished sodium (hyponatremia) levels, the detection of bacteremia in and of itself does not necessarily nor specifically point to any one precise infectious process any more than the other so-called “emias” define the explicit entity that is responsible for an aberrant amount of these ions, which are vital for the functioning of all living cells. In effect, the recognition of their presence merely calls attention to any one of several potentially dangerous pathophysiologic disorders disrupting normal electrolyte homeostasis or, in the case of bacteremia, to the fact that an endogenous or exogenous microbiologic organism has, for an array of possible reasons, invaded the routinely sterile blood. In fact, bacteremia is one of only two microbiology test results (positive cerebrospinal fluid culture being the other) that is included on the list of laboratory-critical values put forth by both the College of American Pathologists and the American Society for Clinical Pathology and adopted and employed by almost all certified laboratories.

“Pneumonitis” denotes inflammation of pulmonary parenchymal tissue, either alveolar or interstitial, resulting from any one of several known pathophysiologic mechanisms. However, in more generic terms, the clinical term “pneumonia” — often described by radiographers as “air space disease” — is conceptualized by most as an infectious disease. Health care providers are led to this diagnostic determination when evaluating patients who present with clinical features such as cough, pleuritic chest pain, dyspnea, fever, hypoxemia, mucopurulent sputum production, leukocytosis, pulmonary auscultatory findings, and the demonstration of a new or changing infiltrative lung process on radiologic chest imaging.

Seventeen years ago, on Oct. 2, 2001, an astute ID physician in Florida made a diagnosis of probable anthrax meningitis in a man who was admitted to the ED. This was accomplished with his old school policy approach of personally looking at the cerebrospinal fluid Gram’s stain. That diagnosis and its consequences, in the wake of the 9/11 attacks on the twin towers and the Pentagon, created headlines around the world. It was the first diagnosed case in a series of anthrax bioterrorism attacks that sickened 22 Americans, killing five, after anthrax spores had been mailed to members of congress, the media and others. That astute ID clinician was my co-author, Larry M. Bush, MD, FACP.

The term “sepsis” has been surrounded by ambiguity and controversy. The condition has instigated legislative policies (eg, “Rory’s Regulations” — a New York state-mandated protocol for ED treatment of sepsis in hospitals), created CMS core quality measures with financial consequences and has been associated with fear and uncertainty on the part of both patients and medical providers. Almost certainly, we have all heard a patient or family member voice their joyful relief that they “don’t have sepsis, but only pneumonia,” unknowing that the medical field uses these two terms interchangeably in some cases.

The easy availability of the urinalysis, usually by dipstick with or without microscopy, has led to its widespread use, often in situations where there is little or no indication for its use. Furthermore, even when indicated for purposes of detecting proteinuria or hematuria or ascertaining specific gravity, there is often the unanticipated finding of pyuria and/or bacteriuria, which then results in further testing or interventions that are usually not indicated.

A recently published governmental study estimated that 2 million persons become ill every year with antibiotic-resistant infections, and about 23,000 die. Antibiotics differ from many other pharmaceutical agents, not only by nature of their critical need, but also by their loss of efficacy over time, thereby requiring continual replacement. In essence, unlike other marketed medications, antibiotics are unique in that once these drugs are approved, their use is actually dissuaded in an effort to preserve their utility.

Intra-abdominal infections, or IAIs, include a variety of entities resulting from disease or trauma to both hollow and solid organs located in either the peritoneal cavity or retroperitoneal space. The designation of “complicated” IAI applies to those conditions that extend beyond the involved organ with subsequent development of secondary peritonitis or abscess formation. Approximately 80% of IAIs are community-acquired, while others, termed health care-associated, generally arise as complications of previous elective or emergency intra-abdominal operations. The later frequently involve nosocomial isolates specific to the site of the operation and individual health care setting. Based upon the patient’s comorbid conditions, immune status and accepted physiologic scoring systems (ie, APACHE-II), IAIs can be graded from mild to moderate to more severe forms. Rapid recognition, optimal hemodynamic restoration, source control and perhaps most importantly, the rapid administration of adequate antimicrobial therapy, best serve to temper morbidity, complications and mortality associated with complicated IAIs. These measures are reflective of what is commonly believed or proven in the management of serious infections leading to sepsis.

There has been a dramatic increase in the number of staphylococcal bacteremias and cases of infective endocarditis involving strains of Staphylococcus aureus resistant to methicillin. Related either to delays in adequate antimicrobial therapy and/or a greater inherent virulence of MRSA compared with methicillin-sensitive strains, most, if not all, evidence and meta-analyses support an overall poorer outcome and increased risk for mortality associated with MRSA as compared with methicillin-sensitive S. aureus bacteremia.